Telephone system



I 1941- w. P. ALBERT TELEPHONE SYSTEM Filed Nov. 15, 1939 3 Sheets-Shes; 1

. INVENTOR By (R ALBERT ATTORNEY July 8, 1941. v Q ALBERT @mmaomsvswm YFiled Nov. 15, 1939 3 Sheets-Sheet 2 INVENTOR By M R ALBERT TORNEY y 'w.P. ALBERT 48,

TELEPHONE SYSTEM Filed Nov. 15, 1939 3 Sheets-Sheer. 3

INVE/V TOR W F. ALBERT B) ATTORNEY Patented July 8, 1941 Walter P.Albert, Madison, Telephone Laboratories,

N J.,. assignor to Hell Incorporated; New

York, N. Y., a corporation of New York Application November 15, 1939,Serial No. 304,461

12 Claims.

This invention relates to the transmission of impulses and particularlytoimpulse repeaters used in telephone systems.

The objects of theinvention are to simplify the structure and theoperation of impulse repeaters; to improve the registration and countingof the impulses; to enable the immediate seizure of a repeater followingitsprevious use without danger of false operation; and otherwise toimprove these devices.

For. some purposes it is desirable to use an impulse repeater in whicheach series of impulses is momentarily stored or registered and is thenretransmitted with necessary corrections for distortion. Usually theincoming series of impulses is registered on a stepping switch whichadvances and marks a terminal corresponding to the number of impulses;and the number of outgoing impulses is counted by a. counting switchwhich steps over its terminals until it reaches the position marked bythe register switch. Since the register switch may advance at a fasterrate than the counting switch, it is necessary to provide some meansto-maintain the stopping position of the register switch in a markedcondition aftersaid switch hasmoved away from that position.

Also it is desirable in a repeater of this kind that the register switchbe capable of starting from any position of rest in responseto-an'incoming series of impulses, and that the counting switch commenceits counting operationlin the. position corresponding to the startingposition of .the'register switch. This requirement is, of course,fulfilled if bothswitches areleft'standing in correspondingpositionsafter each use of the repeater. ;However, it is possible under someconditions for these switches to. stop in positions that do notcorrespond, particularly if the call is abandoned during thetransmission of an impulse series. In such a case it is necessary toprovide special means for bringing the counting switch back into phasewith the register switch before the repeater is available for the nextuse. Should the trunk including the repeater be unguarded during thisinterval of adjustment, a seizure of the trunk for a new call mightresult in mutilation of an' impulse series. On the other hand, if thetrunk is guarded artificially during the time the counting switch isadvanced into phase with the register switch, the'usefulness ofthe trunkis considerably impaired.

. Accordingto a feature of the present invention advantages are. securedover these prior arrangements by a repeater in 1 which the positions oithe register switch. are marked primarilyv by means including. themovable contacts of the switch standing in these positions, and inwhichthemarking is performed. by'a secondary means, such as. discharge tubes,as-rsoon as theregister switch-leavesanytone .o'f itszmarked positionsbefore the counting switch hasreached such posi- .tion. Thisprovisionmakes it unnecessary to use the tube marking means as longas thecounting switch is able to reach-each significant position of theregister switch' before the lattermo-ves .out of. that position;

:A further feature. of. the invention is a re- ..peaterof the'kind abovedescribed provided with means whereby the same terminalseries of theregister and countingswitches that are-used for registeringand countingthe incoming and outgoing; impulses are also utilizedrtozmaintain theseswitches in their proper. phase relation. This-arrangement dispenseswith additional terminal banks for these switches .;and: simplifiesaccordingly the equipment needed for the repeater. .The single terminal"rows of the "register and counting. switches have. their correspondingterminalssmultipled, and a series of dischargetubes are connectedto'these'multiples for the purpose of marking thestarting and stopping.positions of the register switch. The counting switch, which is set inoperation in response'to. themcoming impulse series, hunts for themarked positionsand controlsfthe transmission of a' number of outgoing.impulses corresponding to the number of steps taken .by .the: register"switch.

Another. f eature. of the invention? is an-arranges mentin whichthe-counting switch, if out of phase. with the registerswitch when therepeater is seized, is advanced at a relatively high rate of speeduntilit reaches the startingposition of the register switch. During thispreliminary movement of the counting switch no outgoing impulses aretransmitted. Havingreached the startingv positionof the register switch,the counting switch pauses and then,.if1 the register switch hadadvanced, proceeds at a. slower rate until it reaches the markedstopping position ofthe register switch, and during thissecond advancethe counting switch controls the sending of impulses over theoutgoing'line. .It ispossiblatherefore, that the counting switch willnot overtake'the register switch, that is, that thesynchroni-sm of theseswitches will not be restored until the incoming impulses have beenreceived and registered by the register switch. I With this arrangementit is possible to reseize the repeater without delay, whether theswitches are in phase or out of phase, and without any danger ofmutilating a series of incoming impulses.

These and other features of the invention will be described in detail inthe following specification; also they will be each set forth in theappended claims.

Figs. 1 and 2 of the accompanying drawings illustrate diagrammaticallyan automatic telephone system and disclose in detail one embodiment ofan impulse repeater incorporating the features of this invention; and

Figs. 3 and 4 disclose the structure of the stepping switches used inthe impulse repeater.

The repeater is shown at the incoming end of a trunk T interconnectingan originating automatic oflice with a terminating automatic office. Theoriginating office includes a line-finder switch F and a selector S bymeans of which the calling line I is extended over the trunk T to theterminating ofiice. trunk T may also be provided with an impulserepeater or with the usual trunk control circuit 2.

The incoming impulse repeater in the terminating oifice is interposedbetween the incoming conductors of the trung T and the first selectorswitch Sl. The selector switch 8-! has access through succeedingselectors, if needed, and through the connector switch C to calledsubscribers lines, such as the line 3.

The incoming impulse repeater includes an impulse receiving relay 4which responds to impulses transmitted from the calling subscribersdial. The repeater also includes a register switch 8-4 and a countingswitch S3, each of which comprises a single row of stationary terminals,a stationary contact segment and a movable contact. These switches haveno normal position, the movable contact being capable of starting fromany position and advancing to any stopping position. The movablecontact, such as the contact 5 of switch SZ, engages the stationarysegment 6 at a point intermediate to consecutive stationary terminals ofthe switch. The stepping magnet I when energized disengages the movablecontact 5 from the segment 6 and moves it into engagement with the nextstationary terminal. The following deenergization of the magnet 1 causesthe movable contact 5 to step out of engagement with the stationaryterminal and into engagement with the segment 6. This action continuesfor each energization and deenergization of the magnet I. In a similarmanner the magnet 8 of the switch S3 causes the advance of the movablecontact 9 over the row of stationary terminals and the engagement of thecontact 9 with the stationary segment ill in each resting position ofthe movable contact 9.

The individual terminal in each position of the switch S--2 ismultiplied to the corresponding terminal of switch S3, and the multipleis connected to one electrode of a two-element gasfilled discharge tube.Twenty-two of these gasfilled tubes are illustrated, one for each of thetwenty-two positions of the switches. These tubes mark the terminalpositions of the switches, the designation being obtained by firing thetube connected to the position on which the register switch SZ pausesbetween digits and to which it is desired to advance the counting switch8-3.

The feature, disclosed herein, of utilizing discharge tubes for markingthe switch positions to determine the number of impulses to be sent isclaimed in the patent to Cesareo and Rippere, No. 2,236,499 of April 1,1941. r

The outgoing end of the While the invention is disclosed in an incomingimpulse repeater, it is equally applicable to outgoing repeaters.Moreover, these repeaters may be used in various types of systems andare not limited to the particular system illustrated herein.

Before proceeding with a discussion of the repeater circuits adescription will be given of Figs. 3 and 4 of the drawings, whichillustrate a structure suitable for the switches S-2 and S3. The singlemovable contact 60 of the switch, which corresponds to the contact 5 ofswitch S2 and the contact 9 of the switch S-3, consists of a wire havingenlarged conducting tips 6| and 62 attached to its ends. The contactwire 66 is secured to a shaft 63 which is normally held by the spring 64in its downward position against the operating lever attached to thearmature 66 of the electromagnet 61. The stationary terminals, such asthe terminals 68, 69, H1, H and 12 are arranged in a circular row aroundthe shaft 63 and are insulated from each other and from the movablecontact 60. There may be as many of these terminals as is desired. Forexample, there may be forty-four stationary terminals arranged in acomplete circle around shaft 63. Half of the forty-four terminals may beused, as illustrated in Fig. 2 of the drawings, or the full row ofterminals may be used by connecting diametrically opposite terminalstogether to give parallel contacts for the associated circuit closures.

The rotary stepping motion of the movable contact 66 is caused by seriesof teeth which present camming surfaces to the contact wire 60. Thereare two opposing rows of these cam-shaped teeth. The upper row of teethis formed integrally with the disc I3 which is secured tothe frame ofthe structure in such a way that the successive stationary terminals 16,H, T2, etc., align with the spaces between the successive teeth of thedisc. The lower row of teeth, similarly formed integral with the disc14, is positioned in ofiset relation with respect to the correspondingteeth of the upper row. This relation is best seen in the detail of Fig.4. The switch also includes a conducting ring or segment 15 so disposedthat the conducting tips 6| and 62 rest on the surface thereof when thestepping shaft 63 is in its normal or lowermost position.

Normally, when the magnet 61 is deenergized and the shaft 63 is in itslower position, the movable contact 66 lies between adjacent teeth inthe lower row and is in electrical engagement with the conductingsegment 15. Assume, for example, that the contact wire 60 is at thistime resting between the two adjacent teeth 16 and '11. When the magnet61 is energized, its armature 66, acting through the lever 65, moves theshaft 63 and contact 66 upwardly against the tension of the restoringspring 64. In its upward movement the contact wire 60 engages theslanting surface of the tooth 18 in the upper row, causing the wire 66to rotate until it passes into the slot formed by the tooth 78 and theadjacent tooth 19. The continued upward movement of the wire 66', afterhaving entered the slot, causes it to come to rest in engagement withthe stationary terminal 80 and, of course, into engagement with thecorresponding terminal which lies diametrically opposite the terminal66. When the magnet 67 is subsequently deenergiz'ed, the restoringspring 64 moves the shaft 63 and the contact wire 60 downwardly,whereupon the contact wire 60 engages the slant- 'o'flice. traced frombattery through the upper winding "of relay l6, contact 9, terminal 24,multiple wire ing surface of the tooth 1 1 in the lower row and "rotatesuntil it enters the slot formed by the tooth-11 and "the next tooth 8|,coming finally to rest with the rollers *6'| and 6-2 in engagementsucceeding -energization and 'd'eenerg-ization of the magnet and movablecontact '60 advances in a step-by-step manner around the circular row ofstationary terminals. I Referring now to =Figs. 1 and '2, a detailedde-* scription 'will be given of the operation of the system. For thispurpose it will be assumed that the subscriber of line man originatingtelephone o-ffice wishes to converse with the subscriberof line '3 inadistant orterminatin'g tele- 1 5 phone o'flice. The calling subscriberinitiates the 'call in the 'usual manner and operates theselector-switch Sbymean's of his dial Ilto seize an idle outgoing trunkTextending to'the desired called office. The trunk control circuit 2applies the usual guarding potential to "the test terminal in theselector S and closes the conductors 'of trunk T -to operate the impulserelay "4 of the incoming repeater at the distant The operating circuitof relay 4 may be of the relay, normal contacts of relay 12, trunkconductor I3 thence over "the loop and returning over trunk conductor Mthrough normal contacts of relay l2 and the lower winding of relay *4 toground.

When relay 4 operates, it closes a circuit for "the slow-releaserelay"|5'trac'eab1e from battery through the winding of the latterrelay, closed contacts of relay '4, normal 'contactsof relay |'2 to'groundatthe back'contact of relay l6. Relay "4 also closes parallelcircuits for the immediate energization of r'nagnets "I and '8 and forrelay 31. The circuits for magnets and 8 may 'be traced from-groundthrough the'back contact of relay liiyconductor [1, closed contact ofrelay 4, "conductor 18 thence in parallel through the winding of magnet?and through the back contact "of slow-release relay 1'9, conductor 20,normalcontact of relay'2l through the winding of magnet 8 to battery.Magnet 1 disengages the movable contact 5 from the segment 6 andadvances it into engagement with the next in- 'dividual terminal whichis assumed to be the zero position terminal 23.

It will also be assunied at this time that the switch S--'3 was left inphase with switch 8-2 following the preceding use of the repeater.Therefore, the

'energization of magnet 8 moves the contact 9 out of engagement withsegment ID and into engagement with the zero .pos'ition terminal 24.

As "soon "as relay l5 operates an instant later, a substitute-energizingcircuit is closed for magnet8. Thiscircuit may be traced throughnormalcontacts'of relay 21 andover theconductor ZEi-to ground at thefrom contact of relay t5.

The circuit for relay 3Tmay be traced from conductor 20, normal contactsof relay 30, thence inparallel throughresistances 34 and 35, through:the lower or operating winding of polarized re' lay 31, resistance 38to battery. This circuit 7 causes relay -31 to move its armatureawayfrom its left contact before relay operates and connects ground to thearmature of relay v3-I,

thus-insuring-against false operation of the pulse relay '21.

Since the switches S-2 and 8-3 are in phase, a circuit istraceable fromthe positive pole of 1l0'--volt battery 83, contacts of relay l5 re-;"sistance 25, winding of relay 26, back contacts with the conductingsegment 15. 'With each 5 r I I front contact and armature t-hrough aback con- *the switches S2 and S-3 are in phase, an

21, terminal 23, contact 5, back contacts of slowrelease relay t9,conductor 28 to ground at the front contact of relay 4. Relay 26operates in this circuit and locks in .a circuit through its tact ofrelay I 6, conductor 29 to ground at the from contact of relay |5 Relay26 closes an 30. 'Relay'30 operates relay '34 in a circuit fromconductor 32"to'the grounded conductor 20. A circuit is now closed forslow-release relay 18. This circuit may be traced from "battery throughthe winding of the relay, front contacts of relay 3| to ground at thefront contacts of relay 30. With relays 3| and I6 operated, and sinceoperating circuit is closed for relay 33. This circuit may be tracedfrom battery through the winding of relay 33, front contacts of relaysBI and T6 thence through the contacts of switch S -3 and 8-2 to thegrounded conductor 28.

Relay '33 disconnects the '1'40-volt battery '83 and 34 from conductor28 to prevent the 'firing of :a

tube when the switch S2 starts to advance.

"Relay 33 also locks to ground at its own from contact independent ofthe ground supplied to the conductor 28 at the front contact of relay 4.Relay 33 also closes a holding circuit for relay 33 traceable. frombattery through the winding of the latter relay, front contacts ofrelay33'to ground at the contacts of relay l5. This circuit holds therelay 3|] independentlyof relay 25, which now releases because .its-.operating and locking windings are both opened by the energized relayHi. When relay l6 operates it opens the original energizing circuit ofmagnet I, but the magnet :is maintained energized in a circuit traceableover conductor I 1 "through the front contacts of relay-3| toground.

When relay I5 first operates, :it closes a supplemental circuit bywayofground-over its front contact, conductor 20, normalcontactsof relay3.0 thence in parallel through resistance 34 and resistance 35 throughthe lower or operating winding of relay3'l, resistance 38 tobattery. Asabove noted, current flowing in this direction through the operatingwinding-of relay 3 holds the armature of the relay away from itsleftcontact and right contact in order to place the relay in conditionfor pulsing before ground potential is connected to the armature thereofas will be explained below. The connection of ground potential throughthe operating winding of relay 31 to the junction point of the twowindings causes the condenser 39 to discharge partially through thebiasing Winding aiding in movement of the armature to the right contact.This condenser was previously charged in a circuit from batterythrough-resistanoe 38 through the upper or biasing winding of relay 31to the condenser to ground.

Also at the time relay l5 first operates,--the outgoing pulsing circuitto the switch S| is closed to prepare the switch S| for receiving therepeated series .of impulses. The outgoing pulsing circuit may be tracedfrom conductor-40 through the backcontacts of relays 2| and 3| inparallel, conductor 4 front contacts *of :relay 1:5, conductor 4 2,-normal contactsof relay [6 .to'co'nductor 43. When relay 3|subsequently operates,

of the pulsing circuit is opened, the circuit remaining closed, however,at the normal contacts of pulsing relay 2|. When, still later, relay I6operates, the pulsing circuit is opened temporarily, but the impulserelay associated with the selector S-I is maintained in its energizedcondition over a circuit which is closed prior to the opening of thepulsing circuit. This holding circult is traceable from conductor 40through the front contacts of relay I6, winding of polarized supervisoryrelay I2, front contacts of relay I6 to conductor 43, the front contactsof relay I6 being adjusted to close prior to the opening of its normalcontact. Relay I2, however, does not operate at this time since currentflows in the wrong direction.

When the incoming series of impulses commences, relay 4 releases inresponse to the first impulse and opens the energizing circuit of magnetI and at its back contacts closes an obvious operating circuit forslow-release relay I9. Relay I9 opens the circuit leading to the movablecontact of switch S-2 and also opens the holding circuit of the magnetI. Magnet ,1 deenergizes and steps contact 5 forward to an intermediateposition and the subsequent energizing of magnet 1 will step contact 5to the No. 1 position terminal. For each succeeding impulse in theseries, relay 4 responds, and the magnet I is energized and deenergizedto advance the contact 5 from one terminal to the next. Assuming thatthe first series comprises five impulses, the contact 5 is stepped intoengagement with the fifth position terminal 44, the magnet I being heldenergized following the termination of the series over the circuit abovetraced through the front contact of the impulse relay 4. After theimpulse series is terminated and relay 4 maintains its armaturesattracted for an interval, slowrelease relay I9 releases and closes thetube-firing circuit, which may or may not result subsequently in thefiring of the particular tube selected by the contact 5, depending, aswill be explained hereinafter, upon the rapidity with which thesubscriber transmits the succeeding series of impulses. The tube-firingcircuit may be traced from the positive terminal of 140-volt battery 83,84, resistance 45, normal contacts of relay 33, relay 33 having releasedas will be described presently, closed contacts of relay I5, conductor28, closed contacts of relay I9, contact 5, terminal 44, electrodes ofdischarge tube 46 to ground. The tube 46 does not discharge at this timebecause it is shunted by the ground connection from conductor 28 to thefront contact of relay 4, which is now energized during the intervalbetween digits. Resistance 45 is relatively high to prevent excessivecurrent fiow in the shunt circuit.

When switch S-2 takes its first step in response to the first impulse ofthe incoming series, the counting switch S-3 is set in motion after atime interval to follow switch S2, counting the outgoing impulses untilit reaches the stopping position marked by the switch S-2. The stoppingposition for switch 8-3 is marked by the presence of switch S-2 in thatposition until the latter is in the act of advancing on the secondseries of impulses. At that time it marks the stopping terminal byfiring the tube on which the pause between digits was made but only ifswitch S3 has not yet reached the terminal. When relay I 9 opens its topcontacts before switch S-2 takes its first step, disengaging theterminal 23, it opens the circuit above traced which has been as abovedescribed, one of the parallel branches 'holding the relay 33 energizedand by the same contact opens the firing circuit of the tubes beforerelay 33 releases. Relay 33 releases and opens the holding circuit ofslow-release relay 30. Relay 30 releases after an interval and opens thecircuit of slow-release relay I6, which releases after afurtherinterval. When relay I6 releases, the outgoing series of impulsesis commenced, and the movement of switch S3 begins. The releasing timeof relays 30 and I6 introduces an interval between the start of switchS-2 and the start of switch S3 to insure that the latter does notovertake the formerswitch during the impulse series.

When relay 30 releases, as noted, the grounded conductor 20 is extendedthrough the back contacts of relay 30, resistance 35 through theoperating Winding of relay 31, resistance 38 to battery. The armature ofthe relay 31 again is moved to or is maintained against its rightcontact by the flow of current through the operating winding in thisdirection, and it will be noted that the parallel resistance 34 is nowexcluded from the energizing circuit. A moment later, when relay I6releases, the grounded conductor 29 is extended through the backcontacts of relay I6, back contacts of relay 26, conductor 41, armatureand right contact of relay 31 through the biasing winding of relay 31 tothe condenser 39. Also the application of ground potential to thejunction point of the relay windings causes a reversal of current in theoperating winding, tending to operate the armature to the left contact.Th circuit for the flow of current in the reverse direction may betraced from battery, resistance 56, through the lower winding of relay31, to ground at the junction point. The operating winding, however, isopposed by the flow of current through the biasing Winding while thecondenser 39 is being discharged. It will be noted that the condenser isnormally in a charged or partially charged condition by means of acircuit through resistance 38 and the upper winding of relay 31.

When the condenser approaches a condition of discharge, the operatingwinding of relay 31 moves the armature to the left contact, and theimpulse relay 2| is operated to open the outgoing circuit for thetransmission of the first outgoing impulse. The relay I6 having releasedas above described, the outgoing impulse circuit at this time extendsthrough the closed contacts of relay I6 and the closed contacts ofrelays I5 and 2I. Relay 2| in operating also deenergized the magnet 8 tostep the contact 9 off the terminal 24 and to a position intermediatethe terminal 24 and the next position terminal. When the armature ofrelay v 31 leaves its right contact, current reversal in the operatingwinding tends to move the arma ture back to its right contact. However,the operating winding is opposed at this time by charging currentflowing through the biasing winding to condenser 39. The charging of thecondenser measures the. open period of the outgoing impulse, and, whenthe condenser has reached a state of charge, the operating winding ofthe relay overcomes the biasing winding, and the the position marked bythe switch S2 at the termination of the first impulseseries.

The position to which the switch SZ advances at the endof the firstimpulse series may be marked. in either one of two ways. So long as thecontact remains: standing on the terminal 44,. towhich it advances inresponse to the impulse series, this position is marked by the presenceof a ground potential on the. multiple wire 48- and on the correspondingterminal 49 in the switch 3-3. If, therefore, the subscriber is somewhatslow in transmitting the next digit to cause the second advance ofswitch S-2, switch. S-3 will reach terminal 49- while switch S--2-isstill standing on terminal 44, and the switch S'-3* recognizes thisstopping position by the presence of a direct ground potential on theterminal 49. On the: other hand, if the subscriber is fast with themanipulation of his dial for the second digit, the contact 5 will stepaway fromv the terminal 44 before the switch S-3 arrives on the:terminal 49'. In this case the circults-are soarranged that thecorresponding tube 46' is fired over the contact 5 of which S-Z justbefore the switch leaves terminal 44, and the tube remains in; adischarged condition to provide the ground potential to mark'theterminal 49-, which the switch S-3 will recognize when it subsequentlyarrives. in that position. The operating conditions for both slow andfast dialing will now be explained.

Assume first that the subscriber is slow in manipulatinghis dial for thesecond digit. In this case the switch S-3 will, as explained, reachtheterminal 49 while switch S-2 is still standing on terminal-442 Acircuit is now closed for the detecting relay 26, traceable from thepositivepole of 110-volt battery 83, contacts of relayl5, resistance 25,relay 26, back contactof relay i6, contact 9, terminal 48-, conductor48', terminal 44, contact 5', back contact of relay l9 to the groundedconductor 28. Relay 26 operates in this circuit and locks through itsarmatureand contactan'd a. back contact of relay IE to the groundedconductor 29 Relay 26 in operating removes ground from conductor 41 tostop the pulsing operation byrelays 3'1 and 2l'. It will be noted thatthe. armature of relay 3'! is left in engagement with its right contactat this. time. Relay 26- also operates'relay 30, which: in turnreoperates relay l6; Since switches 8-2 and S--3' are now inphase, thepreviously traced circuit is: closed for reoperating relay 33, thiscircuit extending-through the contacts 9- and 5 to ground; overconductor 28.- Relay l5 releasesrelay 26, but relay- 30. holds throughthe. closed contact ofrelay 33 to the. grounded conductor 29. W-henrelay 33 operates, it prevents the firing of the tube when switchS-Z isabout toleave terminal- 44 on'the next series of pulses. The repeaterhas now reached a: stable condition, the first series having beenreceived and retransmitted, and the repeater remains in: this conditionuntil the commencement of the next series. of impulses.

Assume next that the subscriber is fast in the manipulation of his dialfor the second series ofimpulses, namely, that the first. impulse isreceivedbeforethe switchS-3 reaches-terminal 29. When: the frontcontacts of relay 4' are opened in: response to the first impulse of thesecond series, the ground shunt is removed, and tube 46' discharges overthe circuit previously traced by: way or contact 5- and terminal 44.

Having: discharged.. the tube 46' held, in an ionized condition by acircuit traceable from the positive pole of 1-1-0-volt battery 83',-contact of relay [5, conductor 50 through the high resistanceelement 5|and the tube 46- to ground. Also the opening of the front contacts ofrelay 4 deenergizes the magnet 1- to step the contact 5 ofi the terminal4 4. When: the relay 4 closes its back contacts in response to thefirstimpulse, relayl9- reoperates and opens the tube discharge circuit.It will be noted. that the firing of the tube tomark the stoppingposition of the switch S2:at the end of the impulse. series is delayeduntil the switch is: about totake its first step in response to thesucceeding impulse series. This arrangement economizes in the use. ofthe tubes since it givestheswitch anopportunity to overtake the switchS-l, thus making it unnecessary' to fire the-tube,v and furthermore,since it reduces to a minimum-the interval during which the high firingvoltage is applied to the tube when discharge is necessary. For eachsucceeding impulse in the; second series the relay 4 and magnet Trelease and reoperate, andthe contact 5 advances from one position tothenext. Assuming that the second series comprises six impulses, thecontact. 5 comes to rest on terminal 52.

Returning now to-the operationof switchS-J,

it will be recalledthat this switchcommences to step soon after thebeginning of thefirst seriesof incoming impulses. The switch continuesto step, and outgoing impulses are transmitted as described until thecontact 9" reaches terminal 49. Under the present. assumption theswitch- S-2 has already left the 'correspondingrterminal 44, but thetube 46.- isin a discharged: condition marking this position; When,therefore, contact 9 engages terminal49, a circuit is closed for thetest relay 26; circuit may be traced from'battery 83-, contact: of relay[5-, resistance 2.5-, relay 26-, back contact of'relay l6; contact 9 andterminal 49 of switch S-"-3-,;multiple conductor 48 through thedischarged tube 46 to ground. This circuit including relay 26- isinparallelwith a: circuit through high resistance 5| to tube 46, butsufficient current'fiows in this circuit to operate" the test relay'2-6. The operation-of relay Z6- terminatesthe pulsing as abovedescribed. and. stops the stepping move-- ment of the switch S-i-3-.Relay 26. also closes a locking circuitfrom the positive pole of battery83 through the contact of relay I15, resistance 25-, winding and frontcontact of relay 26, back contact of. relay [6 to. ground on conductor29;

- Relay 26 also closes a circuit for quenching thetube 45- traceablefromvthe grounded-conductor- 29 through the back contaotof relayl6,'locking-. contact of relay 26,. back contact; of relay 16, contact9, terminal 49,. conductor 48- to one electrode of the tube 46, theother electrode also bein connected to. ground. Relay 26 causes thesuccessive operation of relays 30 and 16 as here inbefore described, andrelay IS, in turn, causes the release of relay 26;

Relay 26, having. released following the com-- pletion of thecountingoperation of the switch S-3 for the first digit, and relay- 33failing to operate at this time since the switch S-Zhas already movedaway from terminal 44, relays 3i and i6 commence theirtimed releasetomeasure the pause before-the switch-S3- resumes its operation to countthe second impulse series, which is now being registeredby the advancingswitch S--2. When the relay- I-G' finally-releases, the outgoingimpulses are started, and switch S3 steps from terminal 49 oversucceeding terminals until it reaches terminal 53 which position willhave already been marked by the stopping of switch S3 on its terminal52. If the calling subscriber has not yet begun dialing for the thirddigit, contact 5 is still in engagement with terminal 52, and thecircuit thereinbefore traced is again closed for operating the testrelay 26 to terminate the outgoing impulses and to stop switch S3. Onthe other hand if the calling subscriber has commenced the dialing ofthe third digit, the tube 54 will be in a discharged condition, markingthe stopping position of the switch 8-2 at the end of the second digit,and the test relay 26 operates over a circuit including the dischargedtube 54.

In this manner the successive series of incoming impulses are registeredby the switch 8-2, which steps in synchronism with thecallingsubscribers dialj and the counting switch S- 3 follows the switchS--2 to control the transmission of corresponding outgoing series ofimpulses.

When the last series of incoming impulses has been received, and thesending of the corresponding series of outgoing impulses has beencompleted, the switches S-Z and 8-3 come to rest in the same position.When, therefore, relay l6 operates, following the operation of the testrelay 26, the circuit previously traced is closed for reoperating relay33. Although relay IS in operating causes the release of relay 26, relay33 is held energized and in turn holds relay l6 energizedby reason ofthe fact that relay 33 is now operated. The holding circuit for relay 30may be traced through the closed contacts of relay 33 to the groundedconductor 29. Relay l6 extends the talking conductors 40 and 43 throughto the lower winding of the electropolarized supervisory relay l2, theupper or biasing winding of which is energized over an obvious circuitclosed at the front contact of relay 5.

When the subscriber of the called line 3 answers, the direction ofcurrent is reversed, and relay l2 operates. Relay l2 reverses theconnection of the windings of relay 4 to reverse the direction ofcurrent flowing back over the trunk T, the reversal serving in thewell-known manner to operate supervisory devices in the originatingofiice. Relay l2 releases relay l5, which in turn causes the release ofrelays 3|, 33 and 30 and the release of magnets and 8. Magnets and 8 ondeenergizing advance the contacts 5 and 9, respectively, into engagementwith the conducting segments 5 and I0. Relay 3| opens the circuit ofrelay |6,'but the latter relay, being slow to release, is held in anenergizing circuit which is closed when relay 3| closes its backcontacts. This circuit may be traced from battery through the windingofrelay l6, back contacts of relay 3|, front contacts of relay I6,contact 3, segment l8, segment 6, contact 5, contacts of relay I9,conductor 28 to ground at the front contact of relay 4. The repeaterremains in this condition during the conversational period.

When the calling subscriber replaces his receiver on the switchhook atthe end of conversation, the trunk circuit T is opened, and relay 4releases. Relay 4 releases relay l6, which opens the outgoing trunk tocause the release of the switches S-l and 0.

Although the switches S-2 and S3 are normallyleft in phase, standing inthe same position, following each use of the repeater, it is possiblefor these switches to stop in different positions, particularly if acall is abandoned during the transmission of impulses. In such a casethe switch S-3 would stop an indefinite number of positions back of theswitch S2. On the next seizure of the repeater for a new call the switchS3 is brought into phase with the switch S2, that is, to the startingposition of S2, before any outgoing impulses are transmitted. Toconserve time, this preliminary adjustment of switch S3 is performed ata higher rate of speed.

Assume, for example, that when the repeater is seized the switch 8-2 isstanding before its terminal 44 and that switch S -3 is as shownstanding before its terminal 24. Seizure of the repeater results in theenergization of relay 4, relay I5, and magnets l and 8. Magnet 1advances the contact 5 into engagement with ter- 'minal 44, and magnet 8advances the contact 9 into engagement with terminal 24. Since contacts5 and 9 are in different positions, relay 23 does not operate;consequently, relays 39, 3|, l6 and 33 remain deenergized. Therefore,the pulsing relays 31 and 2| are rendered efiective immediately to stepthe switch S-3. The pulsing speed of the relay 3'! is increased by theinclusion of parallel resistances 34 and 55. The circuit for energizingthe operating winding of relay 31 in the direction to attract thearmature to the right contact now extend-s from grounded conductor 23,through the back contact of relay 38 thence in parallel throughresistances 35 and 34 and the operating winding of relay 3l, resistance38 to the negative pole of battery. The parallel resistance 34 increasesthe current flowing and consequently the speed of operation of thearmature to its right contact. Similarly the circuit through theoperating winding for the flow of current in the opposite direction nowextends over the grounded conductor 41, armature and right contact ofrelay 3! through the operating winding of relay 31 thence in parallelover resistances 56 and 55 to the negative pole of battery. The parallelresistance 55 increases the flow of current to hasten the operation ofthe armature to the left contact. Relay 2| operates in response to eachoperation of relay 31 and steps the switch 8-3 until the contact 9reaches the position 49 corresponding to the starting position of theswitch 8-2.

In the meantime the switch S'2 may be advancing in response to theincoming series of impulses. On the first impulse relay 4 releases andremoves ground from conductor 23, thus removing the shunt around thetube 46. This tube now ionizes in a circuit from the positive pole ofbattery 84, resistance 45, normal contacts of relay 33, front contactsof relay l5, conductor 28, normal contacts of relay l8, contact 5,terminal 44 through the tube 43 to ground. Tube 45 thus marks thestarting position of the switch S-2 in order that the counting switch8-3 may be brought into phase with the starting terminal of switch S-2before outgoing impulses are commenced. During the preliminary steppingmovement of the switch S-3 under the control of relay 2| no outgoingimpulses are transmitted since the contacts of relay 2| are renderedineffective by the short circuit closed at the normal contacts of relay3|. When switch S-3 reaches the starting position of the register switchS2, namely, the position of terminal 49, the test relay 26 operates inthe manner above described either through the ionized tube 45 or togrounded leadlii; Relay 261 stops thestepping action of: the switch andcauses-l the operation of relaystfl, St and Hi. Ifswitch S --2 is stillon terminal 44, relay: 33- operates' in azcirscuit from battery throughits winding, front contacts ofrelays3'l' and I6, contact 9,: terminal:49 through terminal 44, contact 5 to groundon. lead 28. If, however,switch S-2 has: already left terminal 44, relay 26 closes thepreviously" traced circuit for quenching. the fired: tube, and

relay 33 remains deenergized'. Since relay 33- does not operate, relay30"releases, followed by the release of relay It. The pulsing relays 31and 2| now become efiecti've to advance the switch S3 at its lower speedto count the number of outgoing impulses registered by the switch S2.Relay 31 operates at itslower pulse speed because relay' 3 is nowenergized, and: the par-- allel resistances 34 and. 55 are excluded fromthe operating circuits of the relay itself. Alsothe pulsing relay 2| ishow effective to transmit outgoing impulses since relay 3 I is operated,and, the short circuit is removed from the pulsing contacts of relay 2 lIt is possible, although quite unli kel y, due to brief time interval,that the" relay |B= may'operate, following the receipt of a givenseriesof impulses, just as relay dre'lea'ses inwresponse' to the firstimpulse of the succeeding series butbefore relay 33-. has time tooperate. In such a case therelease of relay 4' removes ground fromconductor 28 and allows the tube corresponding to the position taken bycontact 5 to fire before relay l9 operates. Relay l6 having operated,however, the circuit over which a fired tube is normally quenched is notclosed at this time through the locking contact of relay 26 After aninstant relay l9 operates and opens the ionizing circuit of the tube,whereupon the tube is quenched-'im-- mediately by means of a circuittraceable from the negative pole of battery through the winding of relay33, front contacts of relays 31 and I5, contact 9 to the electrodes ofthe ionized tube. The voltage applied to the tube over this circuit isopposite in polarity to the firing and sustaining voltages, and isinsufiicient todei'onize the tube. Hence the ionized tube marking thestopping position of the switch 8-2" is properly quenched before theswitch S'-3 resumes its counting operation for the next outgoing impulseseries.

What is claimed is:

1. The combination in an impulse repeater comprising a register switchhaving a movable contact and a series of position terminals-forregistering successive series of incoming impulses, means responsive toa first impulse series for advancing said movable contact from anyposition to a succeeding stopping position and responsive to furtherseries of impulses for advancing it successively to succeeding stoppingpositions, a primary means and a secondary means for applying a markingcondition to each of said stopping positions, a counting switch having amovable contact and a series of position terminals correspondingrespectively to the'positions of said register switch, circuit means fordetecting a marking condition when applied by either said. primary orsecondary means and for stopping said counting switch, and means forpreventing said secondary means from applying the marking condition ifthe marking condition applied by said primary means hasbeen detected.

2. The combination in an impulse repeater" comprising a registerswitchhavi'ng a movable vancing said movable contact from any positionto a succeeding stopping position and responsive 170? further series ofimpulses for advancing it successively to succeeding. stopping:positions, a-

counting-switch having a movable contact and a series'of positionterminals corresponding respec- 10 tively to the'positions of saidregister switch, dual means of marking the starting and subsequentstopping positions of said register switch, means for operating, saidcounting switch, a test circuit associated with said: counting switchfor detecting: a; position marked by either of said dual means,v andmeans controlled by said test circuit forv stopping said counting switchin the marked position.

3. The combination in an impulse repeater comprising, a register switchhaving a movable:

contact and a series of position'terminals for registering; successiveseries of incoming impulses, means; responsive to-a first impulse seriesfor ad= var-icing said movable contact from any starting position toasucceeding stopping position and responsive to further: series ofimpulses for advancing it. successively" to succeeding stoppingpositions, a; counting. switch having a movable contact' and" a seriesof. position terminals correspondingz'respectively to the positions ofsaid registeri switch", av series of discharge tubes connectedrespectively to the position terminals of said register and countingswitches, means including the movable contact of said register switch!and? effective when said register switch is standing in a given positionfor placing a distinctive marking condition on the terminal of saidposition, means effective before the register switch leavessaid givenposition for operating the corresponding discharge tube to continue thepresence'of the marking condition on the corresponding positionalterminal, means for operating said counting switch, test meansassociated with the counting switch for detecting a marked position ofsaid register switch, and means"controlled by said testing means forstopping the counting switch in the corresponding position.

4; The combination in an impulse repeater comprising a register switchhaving a movable contact and a series of position terminals forregistering successive series of incoming impulses, I

means responsive to a first impulse series for advancing said movablecontact from any starting position to asucceedingstopping position andresponsivetofurther series of impulses for advancing it successively tosucceeding stopping positions, a counting switch having a movablecontactand: a. series of position terminals corresponding respectivelyto-the positions of said register switch, aseries of discharge tubesconnected respectively to' the position terminals of said register andcounting switches, means including a movable contact of said registerswitch and 'ef-' fective when the switch is standing in any start- 1 ingor: s-toppingposition for placing a distinctive condition upon thecorresponding terminal to mark such starting or stopping position, meanseffective whenever the register switch moves away froma starting or astopping position before-the counting switch reaches the correspondingposition for operatingthe corresponding discharge tube to maintain thedistinctive marking condition on the terminal of such position, meansfor operatin the counting switch, a test circuit including the movablecontact of the counting switch for detecting the marked condition of astarting or a stopping position of said register switch, and meanscontrolled by said test circuit for stopping said counting switch in theposition corresponding to said marked position.

5. The combination in an impulse repeater comprising a register switchhaving a movable contact and a series of position terminals forregistering successive series of incoming impulses, means responsive toa first impulse series for advancing said movable contact from anyposition to a succeeding stopping position and responsive to furtherseries of impulses for advancing it successively to succeeding stoppingpositions, a counting switch having a movable contact and a series ofposition terminals corresponding respectively to the positions of saidregister switch, a series of space-discharge tubes common to saidswitches and connected respectively to the position terminals thereof,means for sending out a series of impulses for each incoming series,means responsive to said first series and to each succeedin series ofincoming impulses for causing the advance of said counting switch tocount the outgoing impulses, a circuit including the movable contacts ofboth switches effective to stop said counting switch in each stoppingposition of the register switch if the counting switch reaches suchstopping position before the register switch resumes its advance, meanseifective to ionize the tube at each stopping position of said registerswitch if the register switch advances out of such position before thecounting switch reaches the same, and circuit means including theionized tubes for stopping the counting switch in each stopping positionto which an ionized tube is connected.

6. The combination in an impulse repeater comprising a register switchhaving a movable contact and a series of position terminals forregistering successive series of incoming impulses, means responsive toa first impulse series for advancing said movable contact from anystarting position to a succeeding stopping position and responsive tofurther series of impulses for advancing it successively to succeedingstopping positions, a counting switch having a movable contact and aseries of position terminals corresponding respectively to the positionsof said register switch, a series of discharge tubes connectedrespectively to the position terminals of said register and countingswitches, means including a movable contact of said register switch andeffective when the switch is standing in any starting or stoppingposition for placing a distinctive condition upon the correspondingterminal to mark such starting or stopping position, means effectivewhenever the register switch moves away from a starting or a stoppingposition before the counting switch reaches the cor-' respondingposition for ionizing the corresponding discharge tube to maintain thedistinctve marking condition on the terminal of such position, means foroperating the counting switch, a test circuit including the movablecontact of the counting switch for detecting the marked condition of astarting or a stopping position of said register switch, meanscontrolled by said test circuit for stopping said counting switch in theposition corresponding to said marked position, and means effective whensaid counting switch reaches a position that is marked by an ionizedtube for quenching said tube as soon as the marked position is detected.

7. The combination in a telephone system of an incoming impulse circuit,an outgoing impulse circuit, a register switch comprising a movablecontact and a series of stationary terminals for registering incomingseries of impulses, means responsive to an incoming series of impulsesfor advancing said register switch from any one of said terminals as astarting position over a number of said terminals corresponding to thenumber of impulses, a counting switch comprising a movable contact and aseries of stationary terminals corresponding respectively to thestationary terminals of said register switch, means for marking theterminal to which said register switch is advanced in response to theincoming impulse series and for marking the corresponding terminal ofsaid counting switch, transmitting means for sending impulses over saidoutgoing circuit, means controlled by said transmitting means foradvancing said counting switch from any one of its terminals as astarting position to its marked terminal, means effective when thecounting switch reaches its marked terminal for terminating thetransmission of impulses over said outgoing circuit, and

, means controlled over the movable contact and terminals of saidcounting switch when the starting position thereof difiers from thestarting position of said register switch for advancing the countingswitch to the terminal corresponding to the starting position of saidregister switch prior to the transmission of impulses over said outgoingcircuit.

8. The combination in a telephone system of an incoming impulse circuit,an outgoing impulse circuit, a register switch comprising a movablecontact and a series of stationary terminals for registering incomingseries of impulses, means responsive to an incoming series of impulsesfor advancing said register switch from any one of said terminals as astarting position over a number of said terminals corresponding to thenumber of impulses, a counting switch comprising a movable contact and aseries of stationary terminals corresponding respectively to thestationary terminals of said register switch, means for marking theterminal to which said register switch is advanced in response to theincoming impulse series and for marking the corresponding terminal ofsaid counting switch, transmitting means for sending impulses over saidoutgoing circuit, means controlled by said transmitting means foradvancing said counting switch from any one of its terminals as astarting position to its marked terminal, means effective when thecounting switch reaches its marked terminal for terminating thetransmission of impulses over said outgoing circuit, circuit meanscontrolled by the movable contacts of said register and countingswitches for causing the preliminary advance of said counting switch tothe position corresponding to the starting position of said registerswitch, and means for disabling said impulse transmitting means duringthe preliminary advance of said counting switch.

9. The combination in a telephone system of an incoming impulse circuit,an outgoing impulse circuit, a register switch comprising a movablecontact and a series of stationary terminals for registering incomingseries of impulses, means responsive to an incoming series of impulsesfor advancing said register switch from any one of said terminals as astarting position over a number of said terminals corresponding to thenumber of impulses, a counting switch comprising a movable contact and aseries of stationary terminals corresponding respectively to thestationary terminals of said register switch, means for marking theterminal to which said register switch is advanced in response to theincoming impulse series and for marking the corresponding terminal ofsaid counting switch, transmitting means for sending impulses over saidoutgoing circuit, means controlled by said transmitting means foradvancing said counting switch from any one of its terminals as astarting position to its marked terminal, means effective when thecounting switch reaches its marked terminal for terminating thetransmission of impulses over said outgoing circuit, circut meanscontrolled by the movable contacts of said register and countingswitches for causing the preliminary advance of said counting switch tothe position corresponding to the starting position of said registerswitch, means for disabling said impulse transmitting means during thepreliminary advance of said counting switch, and circuit means efiectivein each stopping position of the counting switch for deionizing thecorresponding tube.

10. The combination in a telephone system of an incoming impulsecircuit, an outgoing impulse circuit, a register switch comprising amovable contact and a series of stationary terminals for registeringincoming series of impulses, means responsive to an incoming series ofimpulses for advancing said register switch from any one of saidterminals as a starting position over a number of said terminalscorresponding to the number of impulses, a counting switch comprising amovable contact and a series of stationary terminals correspondingrespectively to the stationary terminals of said register switch, meansfor marking the terminal to which said register switch is advanced inresponse to the incoming impulse series and for marking thecorresponding terminal of said counting switch, transmitting means forsending impulses over said outgoing circuit, means responsive to theclosure of the incoming impulse circuit if said counting switch is insome position other than the starting position of said register switchfor causing said counting switch to advance at a relatively high speedto the terminal corresponding to said starting position, means fordisabling said impulse transmitting means while said counting switch isadvancing to the starting position, means for causing said countingswitch to advance from said starting position at a relatively low speedto its marked terminal to count the number of impulses transmitted overthe outgoing circuit, and means for rendering said transmitting meanseffective during the movement of said counting switch from the startingposition to its marked terminal.

11. The combination in a telephone system of an incoming impulsecircuit, an outgoing impulse circuit, a register switch comprising amovable contact and a series of stationary terminals for registeringincoming series of impulses, means responsive to an incoming series ofimpulses for advancing said register switch from any one of saidterminals as a starting position over a number of said terminalscorresponding to the number of impulses, a counting switch comprising amovable contact and a series of stationary terminals correspondingrespectively to the stationary terminals of said register switch, aseries of space-discharge tubes common to said switches and connectedrespectively to the corresponding stationary terminals thereof, meansfor discharging the tube connected to the terminal to which the registerswitch advances in response to the impulse series to mark said terminaland the cor- ,responding terminal in said counting switch,

means responsive to the incoming impulse series for advancing thecounting switch from any position in which it may be standing to theterminal marked by the operated discharge tube, impulse transmittingmeans for sending impulses over said outgoing circuit in synchronismwith the movement of said counting switch from its terminalcorresponding to the starting position of the register switch to itsmarked terminal, and means for disabling said impulse transmitting meansduring any preliminary movement of said counting switch necessary toreach said starting position. 7

12. The combination in a telephone system of an incoming impulsecircuit, an outgoing impulse circuit, a register switch comprising amovable contact and a series of stationary terminals for registeringincoming series of impulses, means responsiveto an incoming series ofimpulses for advancing said register switch from any one oi. saidterminals as a starting position over a number of said terminalscorresponding to the number of impulses, a counting switch comprising amovable contact and a series of stationary terminals correspondingrespectively to the stationary terminals of said register switch, aseries of space-discharge tubes common to said switches and connectedrespectively to the corresponding stationary terminals thereof, means,for discharging the tube connected to the terminal to which the registerswitch advances in response to the impulse series to mark said terminaland the corresponding terminal in said counting switch, means eilectiveif the counting switch is standing in some position other than thestarting position when the incoming impulse series is received fordischarging the tube corresponding to said starting position, impulsetransmitting means controlled by said counting switch for sendingimpulses over said outgoing circuit, means for advancing said countingswitch from the position it occupies when the incoming impulses arereceived first to the starting position marked by the last-mentionedtube and then to the position marked by said first-mentioned tube, meansfor rendering said impulse transmitting means ineffective to sendimpulses while said counting switch is moving from its initial positionto the posititon corresponding to the starting position of said registerswitch and for rendering said transmitting means effective to sendimpulses during the movement of the counting switch from said startingposition to the position marked by the incoming impulse series.

WALTER P. ALBERT.

